Air conditioning system

Abstract

The air conditioning system comprises an outdoor unit, a liquid leading-out pipe, a heat recovery pipe, a high-low-pressure air pipe and a low-pressure air pipe, wherein the outdoor unit is provided with a first outdoor heat exchanger, a second outdoor heat exchanger and a compressor; a first indoor unit having a first housing and connected to the outdoor unit via a liquid pipe and a heat recovery pipe; the second indoor unit is provided with a second shell and can be connected with the outdoor unit through a liquid pipe and a high-low-pressure air pipe or connected with the outdoor unit through the liquid pipe, the high-low-pressure air pipe and a low-pressure air pipe; a first indoor heat exchanger disposed in the first housing; a second indoor heat exchanger disposed in the second housing, the first and second indoor heat exchangers being fluidly connected on the liquid pipe side; and the first switching valve, the third outdoor throttling element and the controller are configured to control the second outdoor throttling element and the third outdoor throttling element to act respectively in a heating main body operation mode so as to enable the second outdoor heat exchanger to store, release or lock the refrigerant respectively. The energy utilization rate of the air conditioning system is improved by accurately controlling the flow and the flow direction of the refrigerant.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air conditioning technology, and in particular to an air conditioning system. BACKGROUND

[0002] In a multi-split air conditioning system, there is one outdoor unit and multiple indoor units connected, and the indoor units can be used for cooling or heating as needed. The design of this system allows some indoor units to provide cold air (cooling) and some indoor units to provide warm air (heating) at the same time, thereby meeting the different temperature requirements of the room.

[0003] From the principle point of view, this multi-split air conditioning system achieves the above functions through a complex piping system and valve control. Specifically, low-pressure gas pipes, high-low pressure gas pipes and liquid pipes are used in the outdoor unit and indoor unit of the air conditioning system. By adjusting the valves arranged in the pipeline, the flow direction and flow rate of the refrigerant are controlled, thereby determining whether each indoor unit is cooling or heating. In some models, a cold-heat switching device is also provided to achieve waste heat recovery. The cold-heat switching device is a combination of multiple valves, which is complex in structure. Moreover, when using the cold-heat switching device to achieve waste heat recovery, the user needs to turn on the cooling / heating indoor unit separately, which is complex for the user to operate. SUMMARY

[0004] The present application designs and provides an air conditioning system, specifically a four-pipe multi-scene convertible heat exchanger heat recovery system. The air conditioning system includes an outdoor unit, a first indoor unit and a second indoor unit.

[0005] In one or more embodiments of the present application, the outdoor unit includes a first outdoor heat exchanger, a second outdoor heat exchanger and a compressor, and a liquid pipe, a heat recovery pipe, a high-low pressure gas pipe and a low pressure gas pipe are led out from the outdoor unit; the first outdoor heat exchanger is matched with a first outdoor throttling element, and the second outdoor heat exchanger is matched with a second outdoor throttling element.

[0006] In one or more embodiments of the present application, the first indoor unit has a first housing, and the first indoor unit is connected to the outdoor unit via the liquid pipe and the heat recovery pipe.

[0007] In one or more embodiments of the present application, the second indoor unit has a second housing, and the second indoor unit can be connected to the outdoor unit via the liquid pipe and the high-low pressure gas pipe, or via the liquid pipe, the high-low pressure gas pipe and the low pressure gas pipe.

[0008] In one or more embodiments of the present application, the first indoor heat exchanger is arranged in the first housing.

[0009] In one or more embodiments of the present application, the second indoor heat exchanger is arranged in the second housing, and the first indoor heat exchanger and the second indoor heat exchanger are fluidly connected on the liquid pipe side.

[0010] In one or more embodiments of the present application, a first switching valve is further included, a first port of the first switching valve is connected to a discharge end of the compressor, a second port of the first switching valve is connected to a third port of the first switching valve through an electromagnetic valve and a capillary tube, the third port of the first switching valve is connected to a suction end of the compressor, and a fourth port of the first switching valve is connected to the high-low pressure gas pipe.

[0011] In one or more embodiments of the present application, a third outdoor throttling element is further included, and the third outdoor throttling element is arranged between the first outdoor heat exchanger and the fourth port of the first switching valve.

[0012] In one or more embodiments of the present application, a controller is further included, and the controller is configured to control the second outdoor throttling element and the third outdoor throttling element to act respectively to respectively store, release or lock the refrigerant in the second outdoor heat exchanger in the heating main operation mode.

[0013] In one or more embodiments of the present application, the controller is configured to estimate a real-time state of the heating load rate in the heating main operation mode.

[0014] In one or more embodiments of the present application, the controller is configured to estimate whether a real-time working condition meets a refrigerant storage condition when the heating load rate is lower than a set lower threshold, and control the second outdoor throttling element to be fully opened and the third outdoor throttling element to be fully closed to make the second outdoor heat exchanger store the refrigerant when the real-time working condition meets the refrigerant storage condition.

[0015] In one or more embodiments of the present application, the controller is configured to estimate whether a real-time working condition meets a refrigerant release condition when the heating load rate is higher than a set upper threshold, and control the second outdoor throttling element to be fully closed and the third outdoor throttling element to be fully closed, and make the third outdoor throttling element perform an opening valve operation from a fully closed state to make the second outdoor heat exchanger release the refrigerant when the real-time working condition meets the refrigerant release condition.

[0016] In one or more embodiments of the present application, the controller is configured to estimate whether the third outdoor throttling element reaches a maximum opening degree during the opening valve process of the third outdoor throttling element, and control an opening degree of the second outdoor throttling element according to a superheat degree to keep the third outdoor throttling element fully opened to make the second outdoor heat exchanger release the refrigerant when the third outdoor throttling element reaches the maximum opening degree.

[0017] In one or more embodiments of the present application, the controller is configured to: when the heating load rate is between the set lower threshold value and the set upper threshold value, determine whether the real-time working condition satisfies the refrigerant locking condition; and when the real-time working condition satisfies the refrigerant locking condition, control the second outdoor throttling element to be fully closed, the third outdoor throttling element to be fully closed, and the second outdoor heat exchanger to lock refrigerant.

[0018] In one or more embodiments of the present application, the real-time working condition includes the compressor discharge pressure, the compressor operating frequency, and the difference between the compressor discharge temperature and the corresponding saturated temperature of the compressor discharge pressure.

[0019] In one or more embodiments of the present application, the air conditioning system further comprises an operation terminal, the operation terminal being matched with the second indoor unit, and the operation terminal being used at least to receive a mode selection instruction output by a user; when a heating mode instruction is received, the second indoor heat exchanger works as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators simultaneously; when a cooling mode instruction is received, the second indoor heat exchanger works as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers simultaneously.

[0020] In one or more embodiments of the present application, the air conditioning system further comprises a third indoor heat exchanger, the third indoor heat exchanger being arranged in the second housing, and the first indoor heat exchanger, the second indoor heat exchanger, and the third indoor heat exchanger being fluidly connected on the liquid pipe side.

[0021] In one or more embodiments of the present application, the operation terminal is used at least to receive a mode selection instruction output by a user; when a heating mode instruction is received, the second indoor unit is configured to make only the second indoor heat exchanger work as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators simultaneously; when a cooling mode instruction is received, the second indoor unit is configured to make only the second indoor heat exchanger work as an evaporator, or make the second indoor heat exchanger and the third indoor heat exchanger work as evaporators simultaneously, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers simultaneously; when a dehumidification instruction is received, the second indoor unit is configured to make the second indoor heat exchanger work as a condenser, make the third indoor heat exchanger work as an evaporator, and make the first indoor heat exchanger and the outdoor heat exchanger work as evaporators or condensers.

[0022] In one or more embodiments of the present application, the air conditioning system further comprises a third indoor throttling element, the third indoor throttling element being arranged on the side of the third indoor heat exchanger connected with the liquid pipe.

[0023] In one or more embodiments of the present application, the air conditioning system further comprises a second switching valve, a first port of the second switching valve is connected to the exhaust end of the compressor, a second port of the second switching valve is connected to a third port of the second switching valve through an electromagnetic valve and a capillary tube, the third port of the second switching valve is connected to the suction end of the compressor, and a fourth port of the second switching valve is connected to the outdoor heat exchanger and the heat recovery pipe.

[0024] The air conditioning system provided by the present application has significant advantages in heat recovery and energy efficiency. In addition, under the operation of the heating main body, a refined and flexible control strategy is adopted for the refrigerant, and the energy utilization rate of the air conditioning system is improved through accurate control of the refrigerant flow and flow direction.

[0025] Other features and advantages of the present application will become more apparent after reading the specific embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0028] Figure 2 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0029] Figure 3 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0030] Figure 4 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0031] Figure 5 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0032] Figure 6 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0033] Figure 7 is a structural schematic diagram of the air conditioning system provided by one or more embodiments of the present application;

[0034] Figure 8is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0035] Figure 9 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0036] Figure 10 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0037] Figure 11 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0038] Figure 12 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0039] Figure 13 is a flowchart of an air conditioning system provided by one or more embodiments of the present application;

[0040] Fig. 10, outdoor unit;

[0041] 101-1, first compressor; 101-2, second compressor;

[0042] 102-1, first high-pressure switch; 102-2, second high-pressure switch;

[0043] 103-1, first oil separator; 103-2, second oil separator;

[0044] 104-1, first check valve; 104-2, second check valve;

[0045] 105-1, first capillary tube; 105-2, second capillary tube;

[0046] 106-1, first switching valve; A1, first switching valve first port; B1, first switching valve second port; C1, first switching valve third port; D1, first switching valve fourth port;

[0047] 106-2, second switching valve; A2, first switching valve first port; B2, first switching valve second port; C2, first switching valve third port; D2, first switching valve fourth port;

[0048] 107-1, first outdoor heat exchanger; 107-2, second outdoor heat exchanger;

[0049] 108-1, first outdoor throttling element; 108-2, second outdoor throttling element;

[0050] 109, third outdoor throttling element;

[0051] 110. Subcooler

[0052] 111. Fourth outdoor throttling element

[0053] 112. Liquid accumulator

[0054] 201. First indoor unit; 201-1, first indoor heat exchanger; 201-2, first indoor throttling element

[0055] 202. Second indoor unit; 202-1, second indoor heat exchanger; 202-2, second indoor throttling element

[0056] 203-1, third indoor heat exchanger; 203-2, third indoor throttling element

[0057] 204. First housing; 205, second housing

[0058] 30. Liquid pipe; 31, liquid pipe stop valve

[0059] 40. Heat recovery pipe; 41, heat recovery pipe stop valve

[0060] 50. High-low pressure gas pipe; 51, high-low pressure gas pipe stop valve

[0061] 60. Low pressure gas pipe; 61, low pressure gas pipe stop valve

[0062] 70. Control terminal; 80, programmable logic controller

[0063] 90. Controller DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0065] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0066] The terms "first", "second", etc. are used only to describe the purpose and are not to be interpreted to imply or suggest relative importance or a specific number of the technical features indicated. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0067] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be interpreted broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0068] In the present application, unless otherwise explicitly specified and limited, the "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "on", "above" and "over" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "under", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0069] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to reference numerals and reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and arrangements discussed. In addition, the present application provides various specific examples of processes and materials, but those skilled in the art can realize the application of other processes and the use of other materials.

[0070] In the following, one or more embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0071] Figure 1 is a structural schematic diagram of an air conditioning system according to one or more embodiments of the present application.

[0072] The air conditioning system provided by the application can be applied to public spaces, such as office buildings, museums, hospitals, factories and the like, so as to realize the processing and adjustment of air in the building. The air conditioning system provided by the application is specifically a four-pipe multi-scene convertible heat exchanger heat recovery system.

[0073] With reference to Figure 1 and Figure 2 , the air conditioning system provided by the application comprises an outdoor unit 10, a first indoor unit 201 and a second indoor unit 202.

[0074] The first indoor unit 201 and the second indoor unit 202 can both be in refrigeration operation or heating operation.

[0075] The second indoor unit 202 can perform cooling, heating or dehumidification processing on air and supply the processed air into an air conditioning room.

[0076] The first indoor unit 201 and the second indoor unit 202 can also exchange heat with other media (for example, water) to perform cooling or heating.

[0077] The outdoor unit 10 is described below with reference to the accompanying Figure 1 and Figure 2 .

[0078] With reference to Figure 1 and Figure 2 , the outdoor unit 10 comprises an outdoor heat exchanger and a compressor, and four pipes, namely a liquid pipe 30, a heat recovery pipe 40, a high-low pressure gas pipe 50 and a low pressure gas pipe 60, are led out from the outdoor unit 10. More specifically, a refrigerant circulation pipeline is formed in the outdoor unit 10, and the refrigerant circulation pipeline comprises a first compressor 101-1, a second compressor 101-2, a first oil separator 103-1 and a second oil separator 103-2.

[0079] The first compressor 101-1 and the second compressor 101-2 have a hermetic structure with a built-in motor; low-temperature and low-pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2 respectively, and the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into high-temperature and high-pressure state and discharge the compressed refrigerant gas. Refrigeration oil is arranged in the first compressor 101-1 and the second compressor 101-2, and the refrigeration oil is used to reduce the friction and wear of the first compressor 101-1 and the second compressor 101-2, so as to ensure the normal operation of the first compressor 101-1 and the second compressor 101-2. Two or more than two compressors connected in parallel or more compressors in groups can also be included in the outdoor unit 10. The actual operation frequency of each compressor can be distributed according to the cumulative operation time of each compressor and the preset rotation order.

[0080] A first high pressure switch 102-1 is provided at the discharge end of the first compressor 101-1, and a second high pressure switch 102-2 is provided at the discharge end of the second compressor 101-2. The first high pressure switch 102-1 and the second high pressure switch 102-2 are used to monitor the pressure in the system. When the pressure in the system exceeds a certain threshold, the first high pressure switch 102-1 and / or the second high pressure switch 102-2 will automatically cut off the power supply, stopping the operation of the first compressor 101-1 and / or the second compressor 101-2, to protect the components in the system from damage caused by high pressure. The threshold of the first high pressure switch 102-1 and / or the second high pressure switch 102-2 can be set according to the design parameters and operating conditions of the air conditioning system. Once the pressure in the system is reduced to a safe level, the first high pressure switch 102-1 and / or the second high pressure switch 102-2 will restore the power supply, allowing the first compressor 101-1 and / or the second compressor 101-2 to restart.

[0081] A first oil separator 103-1 is provided at the discharge end of the first compressor 101-1, and a second oil separator 103-2 is provided at the discharge end of the second compressor 101-2. The first oil separator 103-1 and the second oil separator 103-2 are used to separate the refrigerant oil from the refrigerant. Specifically, the first oil separator 103-1 and the second oil separator 103-2 separate the refrigerant oil from the refrigerant by physical separation principles such as centrifugal force or gravity. The separated refrigerant oil is recovered and recycled, while the refrigerant continues to flow.

[0082] A first one-way valve 104-1 is provided downstream of the first oil separator 103-1, and a second one-way valve 104-2 is provided downstream of the second oil separator 103-2, to prevent backflow of the refrigerant.

[0083] A first capillary tube 105-1 is provided in conjunction with the first oil separator 103-1, and a second capillary tube 105-2 is provided in conjunction with the second oil separator 103-2. The first capillary tube 105-1 is connected between the first compressor 101-1 and the first oil separator 103-1, and the second capillary tube 105-2 is connected between the second compressor 101-2 and the second oil separator 103-2. The first capillary tube 105-1 and the second capillary tube 105-2 recover and guide the deposited refrigerant oil into the lubrication system of the first compressor 101-1 and the second compressor 101-2 in the air conditioning system by the principle of adsorption and guidance, achieving the recycling of the refrigerant oil.

[0084] The first oil separator 103-1 and the second oil separator 103-2 can be connected in series with a filter, respectively.

[0085] The second switching valve 106-2 (preferably a four-way valve) receives the refrigerant discharged from the first compressor 101-1 and the second compressor 101-2 through the first oil separator 103-1 and the second oil separator 103-2.

[0086] The second switching valve 106-2 has a second switching valve first port A2, a second switching valve second port B2, a second switching valve third port C2 and a second switching valve fourth port D2; the second switching valve first port A2 is connected to the first oil separator 103-1 and the second oil separator 103-2 in one way and connected to the first switching valve 106-1 in another way; the second switching valve second port B2 is connected to the second switching valve third port C2 through an electromagnetic valve and a capillary tube; the second switching valve third port C2 is connected to the suction end of the first compressor 101-1 and the second compressor 101-2; the second switching valve fourth port D2 is connected to the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 in one way and connected to the heat recovery pipe 40 in another way.

[0087] The first switching valve 106-1 (also preferably realized by a four-way valve) has a first switching valve first port A1, a first switching valve second port B1, a first switching valve third port C1 and a first switching valve fourth port D1; the first switching valve first port A1 is connected to the first oil separator 103-1 and the second oil separator 103-2 in one way and connected to the second switching valve first port A1 in another way; the first switching valve second port B1 is connected to the first switching valve third port C1 through an electromagnetic valve and a capillary tube; the first switching valve third port C1 is connected to the suction end of the first compressor 101-1 and the second compressor 101-2; the first switching valve fourth port D1 is connected to the high-low pressure gas pipe 50.

[0088] The first switching valve 106-1 and the second switching valve 106-2 can have two states of ON and OFF. When in the state of ON, the flow path between the first switching valve first port A1 and the first switching valve second port B1 is conducted, the flow path between the first switching valve third port C1 and the first switching valve fourth port D1 is conducted, similarly, the flow path between the second switching valve first port A2 and the second switching valve second port B2 is conducted, the flow path between the second switching valve third port C2 and the second switching valve fourth port D2 is conducted; when in the state of OFF, the flow path between the first switching valve first port A1 and the first switching valve fourth port D1 is conducted, the flow path between the first switching valve second port B1 and the first switching valve third port C1 is conducted; similarly, the flow path between the second switching valve first port A2 and the second switching valve fourth port D2 is conducted, the flow path between the second switching valve second port B2 and the second switching valve third port C2 is conducted.

[0089] The outdoor unit 10 is provided with a plurality of outdoor heat exchangers arranged in parallel, and exemplarily includes a first outdoor heat exchanger 107-1 and a second outdoor heat exchanger 107-2. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 are connected to the second switching valve fourth port D2 in parallel.

[0090] The first outdoor heat exchanger 107-1 is provided with a first outdoor throttling element 108-1, and the second outdoor heat exchanger 107-2 is provided with a second outdoor throttling element 108-2. The first indoor throttling element 201-2 is arranged on the side of the first indoor heat exchanger 201-1 connected to the liquid pipe 30, and the second indoor throttling element 202-2 is arranged on the side of the second indoor heat exchanger 202-1 connected to the liquid pipe 30.

[0091] The supercooler 110 is connected to the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2. The supercooler 110 is a heat exchanger. The refrigerant flowing through the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 flows to the liquid pipe 30, and the supercooler 110 bypasses the refrigerant flowing to the liquid pipe 30 and then flows into the supercooler 110 again after passing through the fourth outdoor throttling element 111, so that the refrigerant flowing to the liquid pipe 30 is cooled. The fourth outdoor throttling element 111 can be an electronic expansion valve. The bypassed refrigerant can return to the suction end of the first compressor 101-1 and the second compressor 101-2, for example, to the liquid accumulator 112 of the suction end of the first compressor 101-1 and the second compressor 101-2. The liquid accumulator 112 is connected to the first compressor 101-1 and the second compressor 101-2, respectively.

[0092] In one or more embodiments of the present application, the outdoor unit 10 is further provided with a first outdoor fan (not shown) and a second outdoor fan (not shown). The start-stop and rotation speed of the first outdoor fan and the second outdoor fan can be independently controlled, and the air flow of the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 can be changed by adjusting the rotation speed. The first outdoor fan can be a axial fan, a cross-flow fan or other optional fan forms. The first outdoor fan is arranged near the first outdoor heat exchanger 107-1, and the second outdoor fan is arranged near the second outdoor heat exchanger 107-2.

[0093] Referring to the accompanying drawings Figure 1 And Figure 2 The indoor unit is introduced.

[0094] In one or more embodiments of the present application, the first indoor unit 201 has a first housing 204, and a first indoor heat exchanger 201-1 is arranged in the first housing 204. The first housing 204 is provided with a first return air inlet and a first air outlet, and the first air outlet can send air after heat exchange with the first indoor heat exchanger 201-1 into the indoor space or discharge to the external space.

[0095] The first indoor heat exchanger 201-1 is connected to the outdoor unit 10 through a heat recovery pipe 40 (for example, a C-shaped pipe) and a liquid pipe 30, respectively.

[0096] The first indoor heat exchanger 201-1 is matched with a first indoor throttling element 201-2.

[0097] The first indoor unit 201 is further provided with a first indoor fan (not shown), which can be an axial fan or a cross-flow fan.

[0098] The first indoor heat exchanger 201-1 can also exchange heat with other medium, such as water.

[0099] In one or more embodiments of the present application, the second indoor unit 202 has a second housing 205, and a second indoor heat exchanger 202-1 is arranged in the second housing 205. The second housing 205 is provided with a second return air inlet and a second air outlet, and the second air outlet can send air after heat exchange with the second indoor heat exchanger 202-1 into the indoor space.

[0100] The second indoor heat exchanger 202-1 is connected to the outdoor unit 10 through a high-low pressure gas pipe 50 and a liquid pipe 30, respectively.

[0101] The second indoor heat exchanger 202-1 is matched with a second indoor throttling element 202-2.

[0102] The second indoor unit 202 is further provided with a second indoor fan (not shown), which can be an axial fan or a cross-flow fan.

[0103] In one or more embodiments of the present application, the first housing 204 is arranged in a first space, and the first indoor heat exchanger 201-1 can exchange heat with the medium in the first space.

[0104] The second housing 205 is arranged in a second space, and the first space and the second space are independently arranged, and the second indoor heat exchanger 202-1 can exchange heat with the medium in the second space.

[0105] In one or more embodiments of the present application, the first housing 204 is arranged in a first space, and the first air outlet communicates with the external space.

[0106] In one or more embodiments of the present application, the air that has been heat exchanged via the second air supply port into the indoor space can be further introduced into the first shell 204 via the first air return port and discharged to the outdoor space after being heat exchanged with the first indoor heat exchanger 201-1.

[0107] The controller 90 is disposed in a shell with good sealing performance and heat dissipation function. The controller 90 includes a processor, a storage unit, an input / output interface, a communication interface, and the like. The processor can be a special-purpose processor, a central processing unit (CPU), or the like. The processor can access the storage unit to execute instructions or application programs stored in the storage unit to implement related functions, such as driving the frequency of the compressor to operate by a program. The storage unit can include a volatile memory and / or a non-volatile memory. The input / output interface can be in communication connection with various sensors described above to receive detection values of various sensors. The input / output interface is also in communication connection with devices such as the first compressor 101-1 and the second compressor 101-2 to output control instructions generated by the processor. The communication interface can support different wireless communication protocols, such as Wi-Fi, Bluetooth, near field communication, NB-IoT, and the like, to be in communication connection with other electronic devices, including but not limited to a cloud server, a programmable logic controller 9080, a computer (upper computer), a smartphone, a tablet computer, a PDA, a smart control tool, a wearable device, and a vehicle-mounted device, and the like.

[0108] In one or more embodiments of the present application, only the second indoor unit 202 is provided with a control terminal 70, and the first indoor unit 201 is not provided with a control terminal 70. The control terminal 70 is used to control the air conditioning system, including start-stop control, temperature setting adjustment, air volume setting adjustment, receiving mode selection instructions output by the user, mode switching, and the like. The control terminal 70 is fixedly installed indoors, configured with a touch screen or a key, and equipped with a display screen for displaying system operating status and alarm information. The control terminal 70 can also be a remote controller 90, including but not limited to an infrared remote controller, a smartphone, and a smart control terminal, and the like.

[0109] When receiving a heating mode instruction, the second indoor heat exchanger 202-1 works as a condenser, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as evaporators simultaneously; when receiving a cooling mode instruction, the second indoor heat exchanger 202-1 works as an evaporator, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as condensers simultaneously.

[0110] As shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100, a user selects a cooling mode through the control terminal 70, at this time, there are two different cases according to different installation areas of the first indoor unit 201, and air is exemplarily taken as an object medium. Figure 3 and Figure 4 As shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100, a user selects a cooling mode through the control terminal 70, at this time, there are two different cases according to different installation areas of the first indoor unit 201, and air is exemplarily taken as an object medium.

[0111] In the first case, the first indoor unit 201 and the second indoor unit 202 are installed in different indoor spaces. The second indoor heat exchanger 202-1 works as an evaporator, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as condensers.

[0112] From the principle point of view, the low-temperature and low-pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, and the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into a high-temperature and high-pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the ON state, and the second switching valve 106-2 is in the OFF state, and the discharged refrigerant gas flows into the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 through the second switching valve first port A2 and the second switching valve fourth port D2, and the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the condenser state, and the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 condense the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process. The high-temperature and high-pressure state liquid phase refrigerant formed in the condenser flows through the subcooler 110 into the liquid pipe 30 and enters the second indoor unit 202, and in this process, the first outdoor throttling element 108-1, the second outdoor throttling element 108-2 and the second indoor throttling element 202-2 expand the high-temperature and high-pressure state liquid phase refrigerant formed in the condenser into a low-pressure liquid phase refrigerant.

[0113] The refrigerant passing through the second switching valve first port A2 and the second switching valve fourth port D2 also enters the first indoor unit 201 through the heat recovery pipe 40, that is, enters the first indoor heat exchanger 201-1, and the first indoor heat exchanger 201-1 works in the condenser state, and the first indoor heat exchanger 201-1 condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process, and the first indoor unit 201 realizes heating. The high-temperature and high-pressure state liquid phase refrigerant formed in the first indoor heat exchanger 201-1 flows through the first indoor throttling element 201-2, and the first indoor throttling element 201-2 expands the high-temperature and high-pressure state liquid phase refrigerant formed in the first indoor heat exchanger 201-1 into a low-pressure liquid phase refrigerant.

[0114] The expanded low-pressure liquid-phase refrigerant converges into the second indoor heat exchanger 202-1. The second indoor heat exchanger 202-1 works in an evaporator state, and the second indoor heat exchanger 202-1 evaporates the refrigerant expanded in the first outdoor throttling element 108-1, the second outdoor throttling element 108-2, the second indoor throttling element 202-2, and the first indoor throttling element 201-2, and causes the refrigerant in a low-temperature and low-pressure state to return to the first compressor 101-1 and the second compressor 101-2 via the high-low-pressure gas pipe 50, the fourth port D1 of the first switching valve, the third port D3 of the first switching valve, and the liquid accumulator 112. The second indoor heat exchanger 202-1 can exchange heat with the material to be cooled to achieve a refrigeration effect.

[0115] In this case, the heat originally dissipated to the environment by the outdoor unit 10 in the refrigeration mode is partially recovered, and the first indoor unit 201 uses the heat to heat, thereby improving the overall efficiency of the air conditioning system.

[0116] In the second case, the air sent into the indoor (second space) by the second air supply outlet and then exchanged heat is further introduced into the first housing 204 via the first air return outlet, and then discharged to the outdoor after being exchanged heat with the first indoor heat exchanger 201-1. The air temperature of the air sent into the indoor and then exchanged heat via the second air supply outlet is relatively low, and compared with the outdoor heat exchanger working in a condensation state at a high temperature, the condensation effect and capacity of the first heat exchanger as a condenser are obviously improved, so that the air conditioning system can consume less energy to achieve the same effect from an overall perspective, thereby achieving effective heat recovery.

[0117] The first indoor fan and the second indoor fan are controlled in linkage, that is, when the second indoor fan is on standby or stopped, the first indoor fan is also stopped.

[0118] The user selects the heating mode through the control terminal 70, at this time, there are two different cases according to different installation areas of the first indoor unit 201.

[0119] In the first case, the first indoor unit 201 and the second indoor unit 202 are installed in different indoor spaces. The second indoor heat exchanger 202-1 works as a condenser, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as evaporators at the same time.

[0120] From the principle point of view, low temperature and low pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into high temperature and high pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the OFF state, the second switching valve 106-2 is in the ON state, the discharged refrigerant gas passes through the first switching valve first port A1, the first switching valve fourth port D1 into the high-low pressure gas pipe 50, and then enters the second indoor unit 202, flows into the second indoor heat exchanger 202-1, and the second indoor heat exchanger 202-1 works in the condenser state. The second indoor heat exchanger 202-1 condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0121] The high temperature and high pressure state liquid phase refrigerant formed in the condenser returns to the outdoor unit 10 side through the liquid pipe 30. In this process, the second indoor throttling element 202-2, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 expand the high temperature and high pressure state liquid phase refrigerant formed in the condenser into low pressure liquid phase refrigerant. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the evaporator state, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 evaporate the refrigerant expanded in the second indoor throttling element 202-2, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2, and make the refrigerant in low temperature and low pressure state return to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2, the liquid accumulator 112.

[0122] The high temperature and high pressure state liquid phase refrigerant formed in the condenser flows into the first indoor unit 201. In this process, the first indoor throttling element 201-2 expands the high temperature and high pressure state liquid phase refrigerant formed in the condenser into low pressure liquid phase refrigerant. The first indoor heat exchanger 201-1 works in the evaporator state, the first indoor heat exchanger 201-1 evaporates the refrigerant expanded in the first indoor throttling element 201-2, and makes the refrigerant in low temperature and low pressure state return to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2, the liquid accumulator 112.

[0123] In this case, the heat originally dissipated to the environment by the outdoor unit 10 in the heating mode is partially recovered, and the first indoor unit 201 uses this part of the heat for refrigeration, improving the overall efficiency of the air conditioning system.

[0124] In the second case, the air sent into the room by the first air supply port for heat exchange is further introduced into the second shell 205 through the second return air port, and is discharged to the outside after heat exchange with the second indoor heat exchanger 202-1. The air temperature after heat exchange in the room via the first air supply port is relatively high, thereby improving the evaporation effect and capacity of the first heat exchanger as an evaporator, so that the air conditioning system can consume less energy to achieve the same effect, thereby realizing efficient heat recovery.

[0125] The cooperation of the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 can enable the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 to realize refrigerant storage, refrigerant release, and refrigerant locking, and variable storage of refrigerant, so that the refrigerant in the air conditioning system is always at an appropriate level.

[0126] In the above process, the first indoor unit 201 and the second indoor unit 202 are jointly controlled by the control terminal 70, without the participation of the cold-heat switching device, and the user operation is simple and friendly.

[0127] In the above embodiment, the low-pressure gas pipe 60 is kept off and not used. The liquid pipe 30 is provided with a liquid pipe stop valve 31. The high-low pressure gas pipe 50 is provided with a high-low pressure gas pipe stop valve 61. The heat recovery pipe 40 is provided with a heat recovery pipe stop valve 41.

[0128] Only one second indoor unit 202 is shown in the figure, and the same connection mode can be adopted. More first indoor units 201 and second indoor units 202 can also be configured, and the number of the first indoor units 201 and the second indoor units 202 is not limited.

[0129] In one or more embodiments of the present application, at least one of the plurality of parallelly arranged outdoor heat exchangers is provided with a third outdoor throttling element 109 between the first switching valve fourth port; for example, the second outdoor heat exchanger 107-2 and the first switching valve fourth port D2 are provided with a third outdoor throttling element 109.

[0130] In the heating main operation mode, the second outdoor heat exchanger 107-2 can realize corresponding control of refrigerant storage, refrigerant release, and refrigerant locking through the second outdoor throttling element 108-2 and the third outdoor throttling element 109, and can variably store refrigerant in the second outdoor heat exchanger 107-2, so that the refrigerant in the air conditioning system is always at an appropriate level. The heating main operation mode refers to a mode in which the heating load is greater than the cooling load, and the outdoor unit 10 operates in the heating operation mode, that is, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the evaporator state.

[0131] In one or more embodiments of the present application, the controller 90 is configured to control the second outdoor throttling element 108-2 and the third outdoor throttling element 109 to respectively store, release or lock the refrigerant in the second outdoor heat exchanger in the heating main operation mode.

[0132] As shown in FIG. 1, the controller 90 performs the following steps: Figure 5 and Figure 13 As shown in FIG. 1, the controller 90 performs the following steps:

[0133] The opening degree of the second outdoor throttling element 108-2 is controlled according to the superheat degree, and the third outdoor throttling element 109 is kept fully open.

[0134] The real-time state of the heating load rate is estimated.

[0135] If the heating load rate is lower than the set lower threshold, it is further estimated whether the real-time working condition meets the refrigerant storage condition, for example, whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure meet the refrigerant storage condition, and if the refrigerant storage condition is met, the second outdoor throttling element 108-2 is controlled to be fully open, the third outdoor throttling element 109 is controlled to be fully closed, and the excess refrigerant is stored in the second outdoor heat exchanger 107-2.

[0136] If the heating load rate is higher than the set upper threshold, it is further estimated whether the real-time working condition meets the refrigerant release condition, for example, whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure meet the refrigerant release condition, and if the refrigerant release condition is met, the second outdoor throttling element 108-2 is controlled to be fully closed, the third outdoor throttling element 109 is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to perform gradual valve opening operation from the fully closed state to make the second outdoor heat exchanger 107-2 release the refrigerant.

[0137] During the valve opening process, if the refrigerant release condition is no longer met, the current valve opening degree of the third outdoor throttling element 109 is kept unchanged.

[0138] During the valve opening process, it is estimated whether the third outdoor throttling element 109 reaches the maximum opening degree, and if the third outdoor throttling element 109 reaches the maximum opening degree, the opening degree of the second outdoor throttling element 108-2 is controlled according to the superheat degree, and the third outdoor throttling element 109 is kept fully open to release the excess refrigerant in the second outdoor heat exchanger 107-2.

[0139] If the heating load rate is between the set lower limit threshold and the set upper limit threshold, it is further estimated whether the real-time operating conditions meet the refrigerant locking conditions. For example, it is estimated whether the compressor exhaust pressure, the compressor operating frequency, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure meet the refrigerant locking conditions. If the refrigerant locking conditions are met, the second outdoor throttling element 108-2 is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to be fully closed, and the excess refrigerant is locked through the second outdoor heat exchanger 107-2.

[0140] If the air conditioner is not operating in the heating main operation mode, the second outdoor throttling element 108 - 2 and the third outdoor throttling element 109 are both controlled to be in a fully open state.

[0141] like Figure 6 and Figure 7 As shown, in one or more embodiments of the present application, a second indoor heat exchanger 202-1 and a third indoor heat exchanger 203-1 are disposed in the second housing 205. The third indoor heat exchanger 203-1 is connected to the outdoor unit 10 via the low-pressure gas pipe 60 and the liquid pipe 30, respectively. The first indoor heat exchanger 201-1, the second indoor heat exchanger 202-1, and the third indoor heat exchanger 203-1 are fluidically connected on the liquid pipe 30 side. The third indoor heat exchanger 203-1 can operate in an evaporator state, thereby having the following multiple operating modes, such as Figure 8 to Figure 11 shown.

[0142] In the first working mode, the user selects the cooling mode (full load) through the control terminal 70.

[0143] In principle, in the first operating mode, low-temperature, low-pressure refrigerant enters the first and second compressors 101-1, 101-2. These compressors compress the refrigerant into high-temperature, high-pressure refrigerant gas and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the ON state, and the second switching valve 106-2 is in the OFF state. The discharged refrigerant gas flows through the first port A2 and the second port D2 of the second switching valve into the first and second outdoor heat exchangers 107-1, 107-2. The first and second outdoor heat exchangers 107-1, 107-2 operate in the condenser mode, condensing the compressed refrigerant into a liquid phase. Heat is released to the surrounding environment through the condensation process. The high-temperature, high-pressure liquid refrigerant condensed in the condenser flows through the subcooler 110 and enters the liquid pipe 30. In this process, the first outdoor throttling element 108 - 1 and the second outdoor throttling element 108 - 2 expand the liquid-phase refrigerant in a high-temperature and high-pressure state formed in the condenser into a low-pressure liquid-phase refrigerant.

[0144] The refrigerant passing through the second switching valve first port A2 and the second switching valve fourth port D2 also enters the first indoor heat exchanger 201-1 through the heat recovery pipe 40. The first indoor heat exchanger 201-1 works in a condenser state, and the first indoor heat exchanger 201-1 condenses the compressed refrigerant into a liquid phase, and the heat is released to the ambient environment through the condensation process. The first indoor unit 201 realizes heating. The high-temperature and high-pressure liquid phase refrigerant formed by condensation in the first indoor heat exchanger 201-1 flows through the first indoor throttling element 201-2.

[0145] After passing through the second indoor throttling element 202-2 and the third indoor throttling element 203-2 respectively, the expanded low-pressure liquid phase refrigerant enters the second indoor heat exchanger 202-1 and the third indoor heat exchanger 203-1 respectively. The second indoor heat exchanger 202-1 and the third indoor heat exchanger 203-1 work in an evaporator state and evaporate the expanded refrigerant. The second indoor heat exchanger 202-1 makes the refrigerant in a low-temperature and low-pressure state return to the first compressor 101-1 and the second compressor 101-2 through the high-low pressure gas pipe 50, the first switching valve fourth port D1, the first switching valve third port D3, and the liquid accumulator 112. The third indoor heat exchanger 203-1 makes the refrigerant in a low-temperature and low-pressure state return to the first compressor 101-1 and the second compressor 101-2 through the liquid accumulator 112.

[0146] The first working mode can improve the refrigeration capacity of the air conditioning system, that is, to provide a full load working mode.

[0147] The second working mode, the user selects the refrigeration mode (partial load) through the control terminal 70. When the partial load is cut off, the refrigerant flow path of the third heat exchanger, the third heat exchanger stops running, and the working mode of the second heat exchanger is the same as that in the refrigeration mode in the first embodiment, which will not be repeated here.

[0148] The third working mode, the user selects the heating mode through the control terminal 70, cuts off the refrigerant flow path of the third heat exchanger, and the third heat exchanger stops running. The working mode of the second heat exchanger is the same as that in the heating mode in the first embodiment, which will not be repeated here.

[0149] The fourth working mode, the user selects the non-cooling dehumidification mode through the control terminal 70.

[0150] From the principle point of view, the fourth working mode, low temperature and low pressure refrigerant into the first compressor 101-1 and the second compressor 101-2, the first compressor 101-1 and the second compressor 101-2 are compressed into high temperature and high pressure state of refrigerant gas and discharge the compressed refrigerant gas. At this time, the first switch valve 106-1 is in the OFF state, the second switch valve 106-2 is in the ON state, the discharged refrigerant gas passes through the first switch valve first port A1, the first switch valve fourth port D1 into the high and low pressure gas pipe 50, and then flows into the second indoor heat exchanger 202-1, the second indoor heat exchanger 202-1 works in the condenser state. The second indoor heat exchanger 202-1 condenses the compressed refrigerant into liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0151] The high temperature and high pressure state of liquid phase refrigerant formed in the condenser returns to the outdoor unit 10 side through the liquid pipe 30. In this process, the second indoor throttling element 202-2, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 expand the high temperature and high pressure state of liquid phase refrigerant formed in the condenser into low pressure liquid phase refrigerant. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the evaporator state, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 evaporate the refrigerant expanded in the second indoor throttling element 202-2, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2, and make the refrigerant in low temperature and low pressure state return to the first compressor 101-1 and the second compressor 101-2 through the second switch valve fourth port D2 and the second switch valve third port C2, the liquid accumulator 112.

[0152] The high temperature and high pressure state of liquid phase refrigerant formed in the condenser flows into the third indoor heat exchanger 203-1. In this process, the third indoor throttling element 203-2 expands the high temperature and high pressure state of liquid phase refrigerant formed in the condenser into low pressure liquid phase refrigerant. The third indoor heat exchanger 203-1 works in the evaporator state, the third indoor heat exchanger 203-1 evaporates the refrigerant expanded in the third indoor throttling element 203-2, and makes the refrigerant in low temperature and low pressure state return to the first compressor 101-1 and the second compressor 101-2 through the low pressure gas pipe 60, the liquid accumulator 112. The third indoor heat exchanger 203-1 can exchange heat with the material to be cooled to achieve the dehumidification effect, at this time the second indoor heat exchanger 202-1 is in the heating state, and the second indoor unit 202 realizes the dehumidification without temperature drop.

[0153] The high-temperature and high-pressure liquid-phase refrigerant formed in the condenser flows into the first indoor unit 201. In this process, the first indoor throttling element 201-2 expands the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into a low-pressure liquid-phase refrigerant. The first indoor heat exchanger 201-1 operates in an evaporator state, evaporates the refrigerant expanded in the first indoor throttling element 201-2, and causes the refrigerant in a low-temperature and low-pressure state to return to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2, the accumulator 112.

[0154] On the basis of the fourth working mode, in the fifth working mode, the operation of the third indoor heat exchanger 203-1 can be stopped alone, and only the heating operation of the second indoor heat exchanger 202-1 is retained. In this case, the working states of the first switching valve 106-1 and the second switching valve 106-2 are maintained, and the first indoor unit 201 cools.

[0155] In the sixth working mode, the user selects the non-cooling and dehumidifying mode through the control terminal 70.

[0156] From the principle point of view, in the sixth working mode, the low-temperature and low-pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, and the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into a high-temperature and high-pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the OFF state, and the second switching valve 106-2 is in the OFF state. The discharged refrigerant gas flows into the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 through the second switching valve first port A2 and the second switching valve second port D2. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 operate in a condenser state, and the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 condense the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process. The high-temperature and high-pressure liquid-phase refrigerant formed in the condenser flows through the subcooler 110 into the liquid pipe 30. In this process, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 expand the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into a low-pressure liquid-phase refrigerant.

[0157] The refrigerant passing through the second switching valve first port A2 and the second switching valve fourth port D2 also enters the first indoor heat exchanger 201-1 through the heat recovery pipe 40. The first indoor heat exchanger 201-1 works in a condenser state, and the first indoor heat exchanger 201-1 condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process. The first indoor unit 201 realizes heating. The high-temperature and high-pressure liquid-phase refrigerant formed by condensation in the first indoor heat exchanger 201-1 flows through the first indoor throttling element 201-2.

[0158] The refrigerant gas discharged by the compressor enters the second indoor heat exchanger 202-1 through the first switching valve first port A1, the first switching valve fourth port D1, and the high-low pressure gas pipe 50. The second indoor heat exchanger 202-1 works in a condenser state, and the second indoor heat exchanger 202-1 condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process. The high-temperature and high-pressure liquid-phase refrigerant formed by condensation in the second indoor heat exchanger 202-1 flows through the third indoor throttling element 203-2.

[0159] After passing through the first indoor throttling element 201-2 and the third indoor throttling element 203-2, respectively, the expanded low-pressure liquid-phase refrigerant further enters the third indoor heat exchanger 203-1. The third indoor heat exchanger 203-1 works in an evaporator state and evaporates the expanded refrigerant. The third indoor heat exchanger 203-1 causes the refrigerant in a low-temperature and low-pressure state to return to the first compressor 101-1 and the second compressor 101-2 via the low-pressure gas pipe 60 and the liquid accumulator 112.

[0160] Based on the sixth working mode, the seventh working mode can individually stop the operation of the second indoor heat exchanger 202-1, and only the third indoor heat exchanger 203-1 refrigeration (dehumidification) operation is retained. In this case, the working states of the first switching valve 106-1 and the second switching valve 106-2 remain unchanged, and the first indoor unit 201 realizes heating.

[0161] Only one second indoor unit 202 is shown in the figure, and the same connection mode can be adopted. The first indoor unit 201 and the second indoor unit 202 can also be configured with more units, and the number of the first indoor unit 201 and the second indoor unit 202 is not limited.

[0162] In the heating main operation mode, the second outdoor heat exchanger 107-2 can realize corresponding control of refrigerant storage, refrigerant release, and refrigerant locking through the second outdoor throttling element 108-2 and the third outdoor throttling element 109, respectively. The second outdoor heat exchanger 107-2 can variably store refrigerant, so that the refrigerant in the air conditioning system is always at an appropriate level. The heating main operation mode refers to a case where the heating load is greater than the cooling load, and the outdoor unit 10 operates in a heating operation mode.

[0163] The heating load ratio refers to a ratio of a capacity of the indoor unit in the heating state to a total capacity.

[0164] As shown in FIGS. 1, 2, and 3, the controller 90 performs the following steps: Figure 12 Figure 13 As shown in FIGS. 1, 2, and 3, the controller 90 performs the following steps:

[0165] The opening degree of the second outdoor throttling element 108-2 is controlled according to the superheat degree, and the third outdoor throttling element 109 is kept fully open.

[0166] The real-time state of the heating load ratio is estimated.

[0167] If the heating load ratio is lower than the set lower threshold, it is further estimated whether the real-time working condition meets the refrigerant storage condition, for example, whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure meet the refrigerant storage condition, and if the refrigerant storage condition is met, the second outdoor throttling element 108-2 is controlled to be fully open, the third outdoor throttling element 109 is controlled to be fully closed, and the excess refrigerant is stored through the second outdoor heat exchanger 107-2.

[0168] If the heating load ratio is higher than the set upper threshold, it is further estimated whether the real-time working condition meets the refrigerant release condition, for example, whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure meet the refrigerant release condition, and if the refrigerant release condition is met, the second outdoor throttling element 108-2 is controlled to be fully closed, the third outdoor throttling element 109 is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to perform gradual valve opening operation from the fully closed state, so that the second outdoor heat exchanger 107-2 releases the refrigerant.

[0169] During the valve opening process, if the refrigerant release condition is no longer met, the current valve opening degree of the third outdoor throttling element 109 is kept unchanged.

[0170] During the valve opening process, it is estimated whether the third outdoor throttling element 109 reaches the maximum opening degree, and if the third outdoor throttling element 109 reaches the maximum opening degree, the opening degree of the second outdoor throttling element 108-2 is controlled according to the superheat degree, and the third outdoor throttling element 109 is kept fully open, so that the excess refrigerant is released through the second outdoor heat exchanger 107-2.

[0171] ​If the heating load rate is between the set lower limit threshold and the set upper limit threshold, it is further estimated whether the real-time operating conditions meet the refrigerant locking conditions. For example, it is estimated whether the compressor exhaust pressure, the compressor operating frequency, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure meet the refrigerant locking conditions. If the refrigerant locking conditions are met, the second outdoor throttling element 108-2 is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to be fully closed, and the excess refrigerant is locked through the second outdoor heat exchanger 107-2.

[0172] If the air conditioner is not operating in the heating main operation mode, the second outdoor throttling element 108 - 2 and the third outdoor throttling element 109 are both controlled to be in a fully open state.

[0173] In one or more embodiments of the present application, the refrigerant storage conditions include: the compressor exhaust pressure is higher than the first corrected target pressure maximum value, the actual compressor operating frequency is lower than the first set compressor frequency threshold, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure is lower than the first set temperature difference threshold; wherein: the target pressure maximum value is generated based on the temperature difference between the set temperature and the return air temperature of the heating indoor unit, and the greater the temperature difference between the set temperature and the return air temperature, the greater the target pressure maximum value; the first corrected target pressure maximum value is the sum of the target pressure maximum value and the correction value.

[0174] The first set compressor frequency threshold is generated based on a calculated compressor frequency. The calculated compressor frequency is a compressor operating frequency calculated based on an empirical formula according to the current startup load and the corresponding indoor demand.

[0175] For example, the compressor frequency can be calculated using the following empirical formula:

[0176] F C (n) = A × [∑ i (C on (i)×K c (i))]+B×KT×[∑ j (H 。n (j)×K h (j))]+{C×[∑ k (HTh off (k))]+D×[∑ m (H off (m))]}×Khp

[0177] In the above formula, C on (i) is the total operating capacity (HP) of the i-th cooling Thermo ON indoor unit, H on (j) is the total operating capacity of the jth heating Thermo ON indoor unit; HThoff (k) is the kth indoor unit of heating Thermo OFF and the total capacity, in HP; H off (m) is the total capacity of the mth indoor unit of heating stop, in HP, where A, B, C and D are constants.

[0178] Khp is the exhaust pressure correction coefficient, when P d ≥ P do , then Khp=E-(P dmax -P do )×F, where 0.1≤Khp≤1; otherwise Khp=1.

[0179] KT is the outdoor environment temperature correction coefficient, KT=G×T a +H, where G and H are constants.

[0180] K c (i) and K h (j) are the i th indoor unit temperature difference capacity correction coefficients, K c (i) and K h (j) are generated based on the difference between the return air temperature and the set temperature, the greater the absolute value of the difference between the return air temperature and the set temperature, the greater K c (i) and K h (j) are.

[0181] The first set compressor frequency threshold is the product of the calculated compressor frequency and the first proportional coefficient, the first proportional coefficient is a constant obtained under experimental conditions and stored in the form of a constant for ready access, and the first proportional coefficient can be set to be less than 1.

[0182] The first set temperature difference threshold is a constant, and the first set temperature difference threshold is pre-set and stored.

[0183] In one or more embodiments of the present application, the refrigerant release condition includes: the compressor exhaust pressure is lower than the second corrected target pressure maximum value, the actual compressor operating frequency is higher than the second set compressor frequency threshold, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure is higher than the second set temperature difference threshold; wherein: the target pressure maximum value is generated based on the temperature difference between the set temperature and the return air temperature of the indoor unit of heating, the greater the temperature difference between the set temperature and the return air temperature, the greater the target pressure maximum value; the second corrected target pressure maximum value is the difference between the target pressure maximum value and the correction value.

[0184] The set compressor frequency threshold is generated based on the calculated compressor frequency. The calculated compressor frequency is the compressor operating frequency calculated based on an empirical formula according to the current on-load and the corresponding indoor demand.

[0185] The calculated compressor frequency can be calculated by the formula as shown above, which will not be described herein again.

[0186] The second set compressor frequency threshold is a product of the calculated compressor frequency and a second proportional coefficient, and the second proportional coefficient is a constant obtained under experimental conditions and stored in a constant form for ready access. The second proportional coefficient can be set to be greater than 1.

[0187] The second set temperature difference threshold is a constant, and the second set temperature difference threshold is set and stored in advance. The second set temperature difference threshold is higher than the first set temperature difference threshold.

[0188] When neither the refrigerant storage condition nor the refrigerant release condition is satisfied, it is determined that the refrigerant locking condition is satisfied.

[0189] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0190] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. Air conditioning system, characterized in that, include: The outdoor unit comprises: a first outdoor heat exchanger, a second outdoor heat exchanger, and a compressor; a liquid pipe, a heat recovery pipe, high- and low-pressure gas pipes, and a low-pressure gas pipe are led out of the outdoor unit; the first outdoor heat exchanger is matched with a first outdoor throttling element, and the second outdoor heat exchanger is matched with a second outdoor throttling element; a first indoor unit having a first housing, the first indoor unit being connected to the outdoor unit via a liquid pipe and a heat recovery pipe; a second indoor unit having a second housing, wherein the second indoor unit can be connected to the outdoor unit via a liquid pipe and high- and low-pressure gas pipes, or connected to the outdoor unit via a liquid pipe, high- and low-pressure gas pipes, and a low-pressure gas pipe; a first indoor heat exchanger, which is disposed in the first shell; a second indoor heat exchanger disposed in the second housing, the first indoor heat exchanger and the second indoor heat exchanger being fluidly connected on a liquid pipe side; a first switching valve, wherein the first port of the first switching valve is connected to the discharge end of the compressor, the second port of the first switching valve is connected to the third port of the first switching valve through a solenoid valve and a capillary tube, the third port of the first switching valve is connected to the suction end of the compressor, and the fourth port of the first switching valve is connected to the high and low pressure air pipes; a third outdoor throttling element disposed between the first outdoor heat exchanger and the fourth port of the first switching valve; and The controller is configured to control the second outdoor throttling element and the third outdoor throttling element to respectively operate in a heating main operation mode, so as to respectively cause the second outdoor heat exchanger to store refrigerant, release refrigerant or lock refrigerant.

2. The air conditioning system according to claim 1, characterized in that The controller is configured as follows: In the main heating operation mode, the real-time status of the heating load rate is estimated; When the heating load rate is lower than the set lower limit threshold, it is estimated whether the real-time working conditions meet the refrigerant storage conditions; When the real-time working condition meets the refrigerant storage condition, the second outdoor throttling element is controlled to be fully opened and the third outdoor throttling element is controlled to be fully closed, so that the second outdoor heat exchanger stores refrigerant.

3. The air conditioning system according to claim 1, characterized in that The controller is configured as follows: In the main heating operation mode, the real-time status of the heating load rate is estimated; When the heating load rate is higher than the set upper threshold, it is estimated whether the real-time operating conditions meet the refrigerant release conditions; When the real-time working conditions meet the refrigerant release conditions, the second outdoor throttling element is controlled to be fully closed, the third outdoor throttling element is controlled to be fully closed, and the third outdoor throttling element performs valve opening operation from the fully closed state, so that the second outdoor heat exchanger releases refrigerant.

4. The air conditioning system according to claim 3, characterized in that The controller is configured as follows: During the valve opening process of the third outdoor throttling element, estimating whether the third outdoor throttling element has reached a maximum opening degree; When the third outdoor throttling element reaches the maximum opening, the opening of the second outdoor throttling element is controlled according to the superheat, and the third outdoor throttling element is kept fully open, so that the second outdoor heat exchanger releases refrigerant.

5. The air conditioning system according to claim 1, characterized in that The controller is configured as follows: In the main heating operation mode, the real-time status of the heating load rate is estimated; When the heating load rate is between a set lower threshold and a set upper threshold, it is estimated whether the real-time operating condition meets the refrigerant lock condition; When the real-time working condition meets the refrigerant locking condition, the second outdoor throttling element is controlled to be fully closed, and the third outdoor throttling element is controlled to be fully closed, so that the second outdoor heat exchanger locks the refrigerant.

6. The air conditioning system according to any one of claims 2 to 5, characterized in that: The real-time operating conditions include the compressor exhaust pressure, the compressor operating frequency, and the difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure.

7. The air conditioning system according to any one of claims 1 to 5, characterized in that: Also includes: an operation terminal, the operation terminal being matched with the second indoor unit and being at least configured to receive a mode selection instruction input by a user; When receiving a heating mode instruction, the second indoor heat exchanger works as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators at the same time; when receiving a cooling mode instruction, the second indoor heat exchanger works as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers at the same time.

8. The air conditioning system according to claim 1, characterized in that Also includes: The third indoor heat exchanger is disposed in the second shell, and the first indoor heat exchanger, the second indoor heat exchanger and the third indoor heat exchanger are fluidically connected on the liquid pipe side.

9. The air conditioning system according to claim 8, characterized in that Also includes: An operation terminal is matched with the second indoor unit, and the operation terminal is at least used to receive a mode selection instruction output by the user; when receiving a heating mode instruction, the second indoor unit is configured to make only the second indoor heat exchanger work as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators at the same time; when receiving a cooling mode instruction, the second indoor unit can be configured to make only the second indoor heat exchanger work as an evaporator, or make the second indoor heat exchanger and the third indoor heat exchanger work as evaporators at the same time, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers at the same time; when receiving a dehumidification instruction, the second indoor unit can be configured to make the second indoor heat exchanger work as a condenser, make the third indoor heat exchanger work as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators or condensers at the same time.

10. The air conditioning system according to claim 9, characterized in that Also includes: The second switching valve, the first port of the second switching valve is connected to the exhaust end of the compressor, the second port of the second switching valve is connected to the third port of the second switching valve through the solenoid valve and the capillary tube, the third port of the second switching valve is connected to the suction end of the compressor, and the fourth port of the second switching valve is connected to the outdoor heat exchanger and the heat recovery pipe.

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